The prevalence of psychotic, depressive and anxiety syndromes in demented and non‐demented 85‐year‐olds

One‐month prevalence of mental syndromes in demented and non‐demented subjects was studied in a representative sample of 85‐year‐olds living in Gothenburg, Sweden ( N = 494). All subjects were examined by a psychiatrist. Schizophreniform syndrome was significantly more common in subjects with Alzheimer's disease than in nondemented subjects (13% vs 1%, p < 0.001), and more common in severe dementia ( p > 0.01). Depressive syndromes were significantly more common in subjects with mild dementia than in non‐demented subjects (34% vs 20%, p > 0.05). Phobic syndrome was less common in demented than in non‐demented subjects. It is hypothesized that the occurrence of mental syndromes in demented subjects may be related to structural and neurochemical brain changes.